Pulmonary sequestration associated with pulmonary actinomycosis: A case report and literature review

Abstract

Rationale: Pulmonary sequestration (PS), a rare pulmonary disease, arises from congenital pulmonary vascular dysplasia. Meanwhile, pulmonary actinomycosis is a purulent infection of lung lesions triggered by the inhalation of actinomycetes, which is also uncommon. Even rarer is the occurrence of pulmonary actinomycete infection secondary to PS. Herein, we present a case report of such a rare occurrence.

Patient concerns: The 21-year-old female patient had been erroneously diagnosed with pneumonia and tuberculosis, presenting symptoms of cough, sputum, and hemoptysis; however, the implemented anti-infection and antituberculosis treatments proved to be ineffective.

Diagnoses: The diagnosis of the sequestration in the right lower lung was confirmed through an enhanced chest CT scan and a 3-dimensional reconstruction of the pulmonary vessels.

Interventions: During the surgical video-assisted thoracoscopic resection of the right lower lobe lesion, it was discovered that the isolated lung tissue's blood supply vessel originated from the thoracic aorta. Additionally, the pathological examination revealed that the lung tissue of the right lower lobe lesion was infected with pulmonary actinomycetes.

Outcomes: Following thorough evaluation, the patient received a final diagnosis of pulmonary actinomycete infection that occurred secondary to right lower lung sequestration. Consequently, they underwent treatment consisting of high-dose penicillin administered for a period of 6 months post-operation. Over the course of the subsequent 23-month follow-up, no recurrence of the infection or abnormal CT scan findings were observed.

Lessons: Pulmonary sequestration bears clinical resemblance to pulmonary actinomycetes. In cases where recurrent episodes of pneumonia occur at the same location, and chest imaging indicates persistent lesions in the basal segment of the lower lobe near the spine, the possibility of PS should be considered. Prompt chest-enhanced CT and 3-dimensional reconstruction of pulmonary vessels are crucial for a definitive diagnosis. Imaging findings such as mass-like consolidation, cystic lesions, liquefactive necrosis, and pneumonia-like changes, coupled with typical air suspension signs and sulfur-like particles visible under tracheoscopy, suggest a potential pulmonary actinomycete infection. Timely biopsy is essential to confirm the diagnosis and prevent missed or incorrect diagnoses.

Figure 1.

(A, B) The chest CT scan revealed a dense mass-like shadow in the basal segment of the right lower lobe of the lung near the paraspinal column, accompanied by foci of calcification. (C) Bronchoscopy identified congestion and the presence of yellow mucous sputum adhering to the opening of the right lower basal segment. The examination did not reveal any stenotic neoplasms or obstructions within the lumen. (D, E) Enhanced CT of the chest, along with a 3-dimensional reconstruction of the pulmonary vasculature, demonstrated that the arterial blood supply to the right lower basal segment of the lung originated from the thoracic aorta (arrows indicate the abnormal arteries supplying the blood). (F) The postoperative pathology of the right lower lung lesion showed neutrophilic granulocyte exudation in the alveolar lumen, bronchioles, and fine bronchial lumens. The bronchial lumens exhibited radially arranged hyphae, with the tips of the hyphae expanding in a pestle and mortar-like pattern. Some hyphae appeared wrapped up in a mass, consistent with actinomycosis infection. (G, H) A follow-up chest CT on January 17, 2024, revealed postoperative changes in the right lower lung field, with the condition showing stability.